GE D60 - Page 570

8-20 D60 Line Distance Protection System GE Multilin
8.4 SERIES COMPENSATED LINES 8 THEORY OF OPERATION
8
Figure 8–8: DYNAMIC REACH FOR INTERNAL AND EXTERNAL FAULTS
837730A1.CDR
Steady-state
apparent
impedance
R
X
F
A
R
-E
N
D
B
U
S
B
A
R
M
O
V
S
C
R
F
Z
S
C
&
M
O
V
Impedance
Trajectory
The reach is safely
reduced
(a)
Steady-state
apparent
impedance
R
X
F
A
R
-E
N
D
B
U
S
B
A
R
M
O
V
S
C
R
F
Impedance
Trajectory (no
subsynchronous
oscillations)
The reach is not
reduced
Set reach
(b)
Steady-state
apparent
impedance
R
X
F
A
R
-
E
N
D
B
U
S
B
A
R
M
O
V
S
C
R
F
Impedance
Trajectory (no
subsynchronous
oscillations)
The reach is not
reduced
Set reach
(c)
Set reach
LOW-CURRENT EXTERNAL
FAULT
HIGH-CURRENT EXTERNAL
FAULT
HIGH-CURRENT INTERNAL
FAULT